Bis(4-mercaptophenyl)sulfide derivatives, process for the preparation thereof and electronic components

ABSTRACT

The present invention provides a bis(4-mercaptophenyl) sulfide derivative represented by general formula 1. This derivative is a monomer that can form a dielectric film suitable for an electronic component. The present invention further provides a method for producing this derivative and an electronic component having high characteristics under excellent humidity and high temperature.

TECHNICAL FIELD

[0001] The present invention relates to bis(4-mercaptophenyl) sulfidederivatives and a method for producing the same, and an electroniccomponent.

BACKGROUND ART

[0002] Conventionally, a resin film has been used for a dielectric filmin a capacitor or the like. Such a dielectric film is formed byirradiating a monomer deposited in a substrate with electron beams orultraviolet rays to polymerize the monomer, as disclosed in JP 63-32929B, JP 11-147272 A, and U.S. Pat. No. 5,125,138. As the monomer used forforming dielectric films, for example, dimethylol tricyclodecanediacrylate and 1,9-nonanediol diacrylate or the like have been used.

[0003] However, electronic components using the dielectric films formedof the above-described monomers have a problem in that thecharacteristics are not sufficient. In particular, electronic componentsusing the dielectric films formed of the above-described monomers havethe problem that the characteristics are not sufficient under highhumidity and high temperature.

[0004] In order to solve the problem, it is an object of the presentinvention to provide a monomer that can provide dielectric filmssuitable for electronic components and a method for producing the same,and an electronic component having excellent characteristics under highhumidity and high temperature.

DISCLOSURE OF INVENTION

[0005] As a result of in-depth research to achieve the above object, theinventors of the present invention found a novel monomer. To bespecific, the monomer of the present invention is abis(4-mercaptophenyl) sulfide derivative represented by general formula1 below.

[0006] wherein R is hydrogen or a methyl group, and n is an integer of 1to 4.

[0007] The bis(4-mercaptophenyl) sulfide derivative of the presentinvention is preferable as a monomer for forming a dielectric film usedin an electronic component.

[0008] In the bis(4-mercaptophenyl) sulfide derivative of the presentinvention, R may be hydrogen and n may be 2. This embodiment can providea particularly preferable monomer for forming a dielectric film used inan electronic component.

[0009] Furthermore, a method of the present invention for producing abis(4-mercaptophenyl) sulfide derivative includes a first step ofreacting bis(4-mercaptophenyl) sulfide represented by chemical formula 2below with ω-haloalkyl alcohol having not more than 4 carbon atoms,thereby producing an organic compound represented by general formula 3below, and a second step of reacting alkyl ester acrylate or alkyl estermethacrylate with the organic compound represented by general formula 3,thereby producing a bis(4-mercaptophenyl) sulfide derivative of generalformula 1 below.

[0010] wherein n is an integer of 1 to 4.

[0011] wherein R is hydrogen or a methyl group, and n is an integer of 1to 4.

[0012] According to the method of the present invention for producing abis(4-mercaptophenyl) sulfide derivative, the monomer represented bygeneral formula 1 can be produced easily.

[0013] In the method of the present invention, the ω-haloalkyl alcoholmay be 2-haloethanol in the first step, and methyl acrylate may bereacted with the compound represented by general formula 3 in the secondstep. According to this embodiment, the bis(4-mercaptophenyl) sulfidederivative that is particularly preferable as a monomer for forming adielectric film used in an electronic component can be produced easily.

[0014] In the method of the present invention, the first step may beperformed in the presence of alkali metal carbonate, which is a basecatalyst. Furthermore, the second step may be performed in the presenceof alkoxy titanium or an organotin compound, which is a catalyst fortransesterification. According to this embodiment, thebis(4-mercaptophenyl) sulfide derivative can be produced efficiently.

[0015] Furthermore, an electronic component of the present invention isprovided with a dielectric film, wherein the dielectric film is formedby forming a thin film containing at least one type of monomer andpolymerizing the monomer in the thin film, and the monomer has amolecular structure in which sulfur and an aromatic ring are covalentlybonded or a molecular structure in which sulfur and an aromatic ring arebonded via an alkylene group. According to the electronic component ofthe present invention, an electronic component having satisfactorycharacteristics under high humidity and high temperature can beobtained.

[0016] The electronic component of the present invention further mayinclude a pair of electrodes opposed to each other with at least a partof the dielectric film interposed therebetween. This embodiment canprovide an electronic component, such as a capacitor, having excellentcharacteristics even under high humidity and high temperature.

[0017] In the electronic component of the present invention, it ispreferable that the monomer includes one or a plurality of monomersrepresented by general formulae 1 and 4, and chemical formulae 5 and 6.

[0018] wherein R is hydrogen or a methyl group, and n is an integer of 1to 4.

[0019] wherein R is hydrogen or a methyl group.

[0020] This embodiment can provide an electronic component havingparticularly excellent characteristics under high humidity and hightemperature.

[0021] In the electronic component of the present invention, the thinfilm further may include an additive. As the additive, for example, anantioxidant can be used. This embodiment can prevent oxidation of thedielectric film.

BRIEF DESCRIPTION OF DRAWINGS

[0022]FIG. 1A is a cross-sectional view showing an example of acapacitor, which is an electronic component of the present invention.

[0023]FIG. 1B is a cross-sectional view showing another example of acapacitor, which is an electronic component of the present invention.

[0024]FIGS. 2A to 2D are process drawings showing an example of a methodfor producing a capacitor, which is an electronic component of thepresent invention.

[0025]FIG. 3 is a drawing showing one step of the production processshown in FIG. 2.

[0026]FIG. 4A is a cross-sectional view showing yet another example of acapacitor, which is an electronic component of the present invention.

[0027]FIG. 4B is a perspective view of FIG. 4A.

[0028]FIG. 5 is a graph showing the IR spectrum of bis(4-acryloyloxyethylene thiophenyl) sulfide, which is an example of a monomer of thepresent invention used for the production of electronic components.

[0029]FIG. 6 is a graph showing the IR spectrum of 1,4-bis(methacryloyloxyethylene thiomethyl) benzene, which is an example of a monomer of thepresent invention used for production of electronic components.

BEST MODE FOR CARRYING OUT THE INVENTION

[0030] Hereinafter, embodiments of the present invention will bedescribed with reference to the accompanying drawings. In the followingdescription, the same elements bear the same reference numeral andduplicate description may be omitted.

[0031] Embodiment 1

[0032] In Embodiment 1, bis(4-mercaptophenyl) sulfide derivatives of thepresent invention will be described.

[0033] The bis(4-mercaptophenyl) sulfide derivatives of the presentinvention are represented by general formula 1 below.

[0034] wherein R is hydrogen or a methyl group, and n is an integer of 1to 4.

[0035] The bis(4-mercaptophenyl) sulfide derivatives represented bygeneral formula 1 can be produced by the method described in Embodiment2.

[0036] The bis(4-mercaptophenyl) sulfide derivatives represented bygeneral formula 1 can be used as a monomer for forming dielectric films(resin films used in electronic components. When forming a dielectricfilm using this monomer, first, a thin film containing this monomer isformed, and the thin film is irradiated with electron beams orultraviolet rays. Using this monomer, dielectric films suitable forelectronic components can be formed. In particular, when the monomer ofa bis(4-mercaptophenyl) sulfide derivative having hydrogen as R and 2 asn in general formula 1 is used to form dielectric films for capacitors,the capacitors have excellent characteristics even under high humidityand high temperature.

[0037] According to another aspect, the present invention relates toutilization of an organic compound represented by general formula 1 as amonomer of a resin.

[0038] Embodiment 2

[0039] In Embodiment 2, a method for producing the bis(4-mercaptophenyl)sulfide derivatives represented by general formula 1 described inEmbodiment 1 will de described.

[0040] First, an organic compound represented by general formula 3 belowis produced by reacting bis(4-mercaptophenyl) sulfide represented bychemical formula 2 below with o-haloalkyl alcohol, using a base as acatalyst, at 60° C. to 120° C. for four to eight hours (first process).

[0041] wherein n is an integer of 1 to 4.

[0042] The bis(4-mercaptophenyl) sulfide represented by chemical formula2 is commercially available from Sumitomo Seika Chemicals Co., Ltd.under the product name of MPS.

[0043] The ω-haloalkyl alcohol used in the first process is an alcoholhaving a linear carbon chain with 1 to 4 carbon atoms and having ahydroxyl group at a terminal carbon of the carbon chain and halogen atthe other terminal carbon of the carbon chain. More specifically,2-chloroethanol, 3-chloro-1-propanol, 4-chloro-1-butanol,2-bromoethanol, 3-bromo-1-propanol, 2-iodoethanol and the like can beused, for example. The number of carbon atoms of o-haloalkyl alcoholcorresponds to n of the bis(4-mercaptophenyl) sulfide derivatives ofgeneral formula 1. For example, when 2-chloroethanol is used, n ingeneral formula 1 is 2.

[0044] As the base catalyst used in the first process, alkali metalcarbonates such as Na₂CO₃, and K₂CO₃, alkaline earth metal carbonatessuch as CaCO₃ and MgCO₃, and alkali metal alkoxides are suitable. Amongthese, alkali metal carbonates are preferable. As a solvent for the basecatalyst, ketones such as methyl ethyl ketone, methyl isobutyl ketone,ethers such as tetrahydrofuran and dioxane are suitable.

[0045] After the first process, the bis(4-mercaptophenyl) sulfidederivatives of general formula 1 can be produced by refluxing alkylester acrylate or alkyl ester methacrylate and the organic compoundrepresented by general formula 3 in the presence of a catalyst fortransesterification for 6 to 10 hours (second process).

[0046] In the second process, when alkyl ester acrylate (represented bygeneral formula CH₂═CHCOOR′ in which, for example, methyl groups, ethylgroups, propyl groups, butyl groups or the like can be used for R′ as analkyl group), preferably, methyl acrylate is used, bis(4-mercaptophenyl)sulfide derivatives having hydrogen as R can be obtained. Alternatively,when alkyl ester methacrylate (represented by general formulaCH₂═C(CH₃)COOR″ in which, for example, methyl groups, ethyl groups,propyl groups, butyl groups or the like can be used for R″ as an alkylgroup), preferably, methyl methacrylate is used, bis(4-mercaptophenyl)sulfide derivatives having a methyl group as R can be obtained.

[0047] As the catalyst for transesterification used in the secondprocess, alkoxy titanium such as tetrabutyl titanate, and organotincompounds such as dibutyltin oxide, dioctyltin oxide, dibutyltindiacetate, dibutyltin dilaurate are suitable. Among these, tetrabutyltitanate or dibutyltin oxide is preferable. As the amount of alkyl esteracrylate (or alkyl ester methacrylate) to be fed, 3 to 10 parts byweight per part by weight (by mass) of the organic compound of generalformula 3 is preferable.

[0048] In the above-described production method, it is preferable thatω-haloalkyl alcohol is 2-haloethanol in the first process, and methylacrylate is reacted with the compound represented by general formula 3in the second process.

[0049] The production method of Embodiment 2 can facilitate productionof the bis(4-mercaptophenyl) sulfide derivatives of general formula 1described in Embodiment 1.

[0050] Embodiment 3

[0051] In Embodiment 3, an example of a capacitor will be described asan electronic component of the present invention. FIG. 1A is across-sectional view of a capacitor 10 of Embodiment 3. The capacitor ofthe present invention can have a shape as shown in FIG. 1B as acapacitor 10 a.

[0052] Referring to FIG. 1A, the capacitor 10 includes a support 11, alower electrode film 12 formed on the support 11, a dielectric film 13disposed mainly on the lower electrode film 12, and an upper electrodefilm 14 disposed mainly on the dielectric film 13. The dielectric film13 is a resin film (an additive may further be included in the resinfilm). In other words, the capacitor 10 includes the dielectric film 13and a pair of electrodes (the lower electrode film 12 and the upperelectrode film 14) that are opposed with the dielectric film 13interposed therebetween.

[0053] As the support 11, various substances can be used. Morespecifically, for example, films made of polymer such as polyethyleneterephthalate (which may be referred to as “PET” in the following),polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polyamide(PA) or polyimide (PI) can be used. There is no limitation regarding thethickness of the support 11, but in general, a thickness of the order of1 μm to 75 μm commonly is used. When the lower electrode film 12 alsoserves as the support, the support 11 is not required. The support 11can be removed after the lower electrode film 12, the dielectric film 13and the upper electrode film 14 are formed. In other words, thecapacitor of the present invention may not be provided with the support.

[0054] For the lower electrode film 12 and the upper electrode film 14,conductive films can be used. For example, metal films can be used. Morespecifically, metal films containing aluminum, zinc, copper or the likeas the main component can be used. There is no particular limitationregarding the thickness of the electrode films, but for example, filmshaving a thickness of 10 nm to 150 nm can be used, and preferably, filmshaving a thickness of 20 nm to 50 nm can be used. The lower electrodefilm 12 and the upper electrode film 14 of the capacitor 10 areconnected to respective electric circuits. The electrode films can beconnected to the electric circuits by, for example, soldering, metalspraying, clamping or the like.

[0055] The dielectric film 13 is a resin film formed by forming a thinfilm containing at least one type of monomer and then polymerizing themonomer in the thin film. The monomer has a molecular structure in whichsulfur and an aromatic ring are covalently bonded or a molecularstructure in which sulfur and an aromatic ring are bonded via analkylene group. The thin film may contain one type of monomer or aplurality of types of monomers.

[0056] A thin film 13 a (see FIG. 2B) that will be formed into thedielectric film 13 by polymerization reaction further may contain anadditive, in addition to the monomer. Examples of the additive includepolymerization initiators, antioxidants, plasticizers, surfactants, andadhesion improvers. As a polymerization initiator, for example,2-benzyl-2-dimethylamino-1-(4-orpholino phenyl)-butanone-1,bis(2,4,6-trimethyl benzoyl)-phenyl phosphine oxide,2-methyl-1[4-(methylthio)phenyl]-2-morpholino propane-1-one (which areIrgacure 369, 819 and 907, respectively, manufactured by Ciba SpecialtyChemicals) can be used. As an antioxidant, for example,octadecyl-3-(3,5,-di-tert-butyl-4-hydroxyphenyl) propionate, benzenepropanoic acid, 3,5-bis(1,1-dimethyl ethyl)-4-hydroxy, C₇ to C₉ sidechain alkyl ester, 4,6-bis(octylthio methyl)-o-cresol (which areIRGANOX-1076,1135, and 1520L, respectively, manufactured by CibaSpecialty Chemicals) can be used.

[0057] In the case where the thin film 13 a contains a polymerizationinitiator, the content of the polymerization initiator preferably is0.5% by weight (% by mass) to 10% by weight, and more preferably 1% byweight to 3% by weight. When the content of the polymerization initiatoris 0.5% by weight or more, the curing rate of the thin film 13 a can beincreased. When the content of the polymerization initiator is 10% byweight or less, the pot life of the monomer 31 (see FIG. 3) can beprevented from being too short. When the content of the polymerizationinitiator is 1% by weight to 3% by weight, the curing rate can beincreased and the pot life of the monomer 31 can be prevented from beingtoo short, and thus the capacitor 10 can be produced easily.

[0058] In the case where the thin film 13 a contains an antioxidant, thecontent of the antioxidant preferably is 0.1% by weight to 10% byweight, and more preferably 0.5% by weight to 5% by weight. When thecontent of the antioxidant is 0.1% by weight or more, the dielectricfilm 13 can be prevented from being oxidized. When the content of theantioxidant is 10% by weight or less, the curing rate of the thin film13 a can be a practical value. When the content of the antioxidant is0.5% by weight or more, the dielectric film 13 can be prevented frombeing oxidized remarkably. When the content of the antioxidant is 5% byweight or less, the curing rate of the thin film 13 a can be apreferable value.

[0059] As the monomer contained in the thin film 13 a, for example,monomers represented by general formulae 1 and 4 and chemical formulae 5and 6 can be used.

[0060] wherein R is hydrogen or a methyl group, and n is an integer of 1to 4.

[0061] wherein R is hydrogen or a methyl group.

[0062] The monomers of general formula 1 can be produced by the methoddescribed in Embodiment 2. The monomers of general formula 4 can beproduced by a method as described below. The monomers of chemicalformulae 5 and 6 are commercially available from Sumitomo SeikaChemicals under the products names of MPV and MPSMA, respectively.

[0063] For the monomers of general formula 1, it is especiallypreferable that R is hydrogen and n is 2. The thin film 13 a can containthe monomers of general formulae 1 and 4 and chemical formulae 5 and 6in an arbitrary ratio, and for example, can contain the monomer ofgeneral formula 1 in a ratio of 50% by weight or more and furthercontain the monomer of general formula 4.

[0064] Hereinafter, a method for producing the monomers of generalformula 4 will be described. First, an intermediate product representedby chemical formula 7 below is produced by reacting p-xylene dichloridewith 2-mercaptoethanol in the same manner as in the first process forproducing the monomers of general formula 1.

[0065] Thereafter, this intermediate product is reacted with methylacrylate or methyl methacrylate in the same manner as in the secondprocess for producing the monomers of general formula 1, and thus themonomer of general formula 4 can be synthesized easily.

[0066] Next, a method for producing the capacitor 10 will be described.FIGS. 2A to 2D show an example of the production process.

[0067] Referring to FIG. 2A, first, the lower electrode film 12 isformed on the support 11. The lower electrode film 12 can be formed byvacuum evaporation such as electron beam evaporation, resistance heatingevaporation, and induction heating evaporation, ion plating, sputtering,plating or the like. In order to form the lower electrode film 12 into apredetermined shape, a metal mask can be used, or photolithography,etching or other techniques can be used.

[0068] Next, as shown in FIG. 2B, the thin film 13 a containing amonomer is formed on the lower electrode film 12. The thin film 13 a isa film that will be formed into the dielectric film 13 by apolymerization reaction, and contains the above-described monomersrepresented by general formulae 1 and 4 and chemical formulae 5 and 6and additives. The thin film 13 a can be formed by placing a container32 containing a monomer 31 for forming the thin film 13 a under a vacuumsuch that the container 32 faces the lower electrode film 12, as shownin FIG. 3, and heating the container 32 to evaporate the monomer. Ametal mask (not shown) can be used to form the thin film 13 a into apredetermined shape.

[0069] Then, a polymerization reaction of the monomer is caused in thethin film 13 a, and thus the dielectric film 13 is formed, as shown inFIG. 2C. The polymerization reaction (curing) can be caused by, forexample, irradiating the thin film 13 a with ultraviolet rays orelectron beams.

[0070] Next, as shown in FIG. 2D, the upper electrode film 14 may beformed in the same manner as the lower electrode film 12 is formed.Thus, the capacitor 10 can be produced. The capacitor 10 a can beproduced by the same production method.

[0071] In the capacitor of Embodiment 3, the dielectric film 13 hardlyis changed in its properties even under high humidity or hightemperature, and thus a capacitor having excellent characteristics evenunder high humidity and high temperature can be obtained.

[0072] Embodiment 4

[0073] In Embodiment 4, another example of a capacitor will be describedas an electronic component of the present invention. FIG. 4A is across-sectional view of a capacitor 40 of Embodiment 4, and FIG. 4B is aperspective view thereof. The same aspects as described in Embodiment 3will not be described further.

[0074] Referring to FIGS. 4A and 4B, the capacitor 40 includes adielectric film 41 (hatching is omitted), a plurality of electrodes 42 adisposed in the dielectric film 41, electrodes 42 b opposed to theelectrodes 42 a, and external electrodes 43 a and 43 b connected to theelectrodes 42 a and 42 b, respectively. In other words, the capacitor 40includes at least one pair of electrodes opposed to each other with atleast a part of the dielectric film 41 interposed therebetween. Thecapacitor 40 further includes metal thin films 44 disposed on the outersides of the electrodes 42 a and 42 b. The portion of the capacitor 40in which the plurality of electrodes 42 a and the electrodes 42 bopposed to the electrodes 42 a are present serves as an element layer 40a. The portions of the capacitor 40 in which the metal thin films 44 areformed serve as reinforcing layers 40 b. The portions of the capacitor40 that are constituted only by the dielectric film 41 serve asprotective layers 40 c. The reinforcing layers 40 b and the protectivelayers 40 c are layers for preventing the element layer 40 a from beingdamaged by thermal load or external force. It is possible that thereinforcing layers 40 b or the protective layers 40 c are not providedin the capacitor 40.

[0075] The dielectric film 41 is the same film as the dielectric film 13described in Embodiment 3 and can be produced by the same method asabove.

[0076] The capacitor 40 can be produced by the method described inEmbodiment 3. However, the method for producing the capacitor 40 isdifferent from the method described in Embodiment 3 in that it isnecessary to laminate the dielectric films and the electrodes 42 a or 42b alternately and to form the external electrodes 43 a and 43 b in themethod for producing the capacitor 40. The external electrodes 43 a and43 b can be formed by, for example, performing metal spraying, formingbump electrodes, applying conductive paste or other techniques.

[0077] In the capacitor 40 of Embodiment 4, the dielectric film 41hardly is changed in its properties even under high humidity or hightemperature, and thus a capacitor having excellent characteristics evenunder high humidity or high temperature can be obtained.

EXAMPLES

[0078] Hereinafter, the present invention will be described morespecifically by way of examples.

Example 1

[0079] In Example 1, an example of the production of a monomer that is abis(4-mercaptophenyl) sulfide derivative represented by general formula1 and has hydrogen as R and 2 as n will be described. Also, an exampleof the production of a monomer that is a bis(4-mercaptophenyl) sulfidederivative represented by general formula 1 and has a methyl group as Rand 4 as n will be described.

[0080] First, 25.0 g (0.10 moles) of the bis(4-mercaptophenyl) sulfiderepresented by chemical formula 2, 16.1 g (0.20 moles) of2-chloroethanol, 27.6 g (0.20 moles) of potassium carbonate, and 300 mlof methyl isobutyl ketone were placed in a flask with a volume of 1liter and reacted by continuous stirring under reflux for 6 hours. Aftercompletion of the reaction, 50 ml of a 5% hydrochloric acid solution wasadded gradually to the obtained solution under stirring. Thereafter, 300ml of toluene was added thereto. The thus obtained solution was washedwith distilled water repeatedly until the pH reached 7. Then, the washedsolution was dried with anhydrous sodium sulfate, and the solvent wasremoved by distillation. Thus, the intermediate product represented bychemical formula 8 below was obtained in an amount of 32 g.

[0081] Then, 320 g of methyl acrylate, 0.32 g of tetrabutyl titanate({fraction (1/100)} parts by weight with respect to the intermediateproduct), and 0.16 g of p-methoxyphenol ({fraction (5/1000)} parts byweight with respect to the intermediate product) as a polymerizationinhibitor were added to 32 g of the intermediate product represented bychemical formula 8, followed by 10 hour reflux, and then methyl acrylatewas removed by distillation. The thus obtained reaction product wasdissolved in 300 ml of toluene, and then this solution was washedsequentially, first with 50 ml of a 5% sodium hydroxide solution andthen with 50 ml of a 5% hydrochloric acid solution. Further, thesolution was washed with distilled water until the pH reached 7, andthen dried with anhydrous sodium sulfate. To this solution, 0.16 g ofp-methoxyphenol was added, and thereafter, the solvent was removed bydistillation. Thus, a semi-solid having a melting point of 20° C. wasobtained. This semi-solid was measured by infrared spectroscopicanalysis and gel permeation chromatography (GPC).

[0082]FIG. 5 shows the results of measurement by infrared spectroscopicanalysis. As seen from FIG. 5, an absorption peak at 1725 cm⁻¹ based onester acrylate was observed. In GPC, the raw material, the intermediateproduct and byproducts were not detected. From the aspects describedabove, the finally obtained semi-solid turned out to bebis(4-acryloyloxyethylene thiophenyl) sulfide represented by chemicalformula 9 below.

[0083] Next, an example of production of bis(4-methacryloyloxybutylenethiophenyl) sulfide that is an organic compound represented by generalformula 1 and has a methyl group as R and 4 as n will be described.

[0084] In this case, the same method as that for producing thebis(4-acryloyloxyethylene thiophenyl) sulfide represented by chemicalformula 9 can be used except that a different raw material is used. Morespecifically, 2-chloroethanol was replaced by 4-chloro-1-butanol, andmethyl acrylate was replaced by methyl methacrylate. Thus,bis(4-methacryloyloxy butylene thiophenyl) sulfide represented bychemical formula 10 was obtained.

Example 2

[0085] In Example 2, an example of production of a monomer that isrepresented by general formula 4 and has a methyl group as R will bedescribed.

[0086] First, 17.5 g (0.10 moles) of p-xylene dichloride, 15.6 g (0.20moles) of 2-mercaptoethanol, 27.6 g (0.20 moles) of potassium carbonate,and 300 ml of methyl isobutyl ketone were placed in a flask with anvolume of 1 liter and reacted by continuous stirring under reflux for 6hours. After completion of the reaction, the obtained solution wastreated in the same manner as in Example 1, and thus, the intermediateproduct represented by chemical formula 7 below was obtained in anamount of 23 g.

[0087] Then, 230 g of methyl acrylate, 0.23 g of tetrabutyl titanate({fraction (1/100)} parts by weight with respect to the intermediateproduct), and 0.12 g of p-methoxyphenol ({fraction (5/1000)} parts byweight with respect to the intermediate product) as a polymerizationinhibitor were added to 23 g of the intermediate product represented bychemical formula 7, followed by 10 hour reflux, and methyl methacrylatewas removed by distillation. The thus obtained reaction product wastreated in the same manner as in Example 1, and thus, a transparentlight yellow liquid was obtained. This liquid was measured by infraredspectroscopic analysis and GPC.

[0088]FIG. 6 shows the results of measurement by infrared spectroscopicanalysis. As seen from FIG. 6, an absorption peak at 1725 cm⁻¹ based onester methacrylate was observed. In GPC, the raw material, theintermediate product and byproducts were not detected. From the aspectsdescribed above, the finally obtained liquid turned out to be1,4-bis(methacryloyloxyethylene thiomethyl) benzene represented bychemical formula 11 below.

[0089] The monomer of general formula 1 having hydrogen as R can beproduced by the same method as the above-described method except thatmethyl acrylate, instead of methyl methacrylate, is reacted to theintermediate product represented by chemical formula 7.

Example 3

[0090] In Example 3, an example of production of the capacitor shown inFIG. 1A as an electronic component of the present invention will bedescribed with reference to FIGS. 2A to 2D.

[0091] First, a PET substrate 11 having a thickness of 25 μm wasprepared, and the lower electrode film 12 (30 nm thick) made of aluminumwas deposited on the PET substrate 11 by evaporation at a depositionrate of 100 nm/sec. (see FIG. 2A).

[0092] Thereafter, the thin film 13 a (200 nm thick) made of the monomerwas formed on the lower electrode film 12 by evaporating the monomer(see FIG. 2B). More specifically, the container 32 containing themonomer 31, as shown in FIG. 3, was heated such that the deposition ratebecame 500 nm/sec., and the thin film 13 a was formed such that a partof the lower electrode film 12 was exposed.

[0093] Thereafter, the thin film was irradiated with acceleratedelectrons at −15 kV at a density of 50 μA/cm² for 2 seconds topolymerize the monomer in the thin film, and thus the dielectric film 13was formed (see FIG. 2C).

[0094] Thereafter, the upper electrode film 14 made of aluminum wasformed in a position that is above the dielectric film 13 and is not incontact with the lower electrode film 12 by evaporation at a depositionrate of 100 nm/sec. (see FIG. 2D).

[0095] In Example 3, 5 different capacitors were produced, using themonomer of chemical formula 9, the monomer of chemical formula 11, themonomer of chemical formula 11 containing 3% by weight of IRGANOX 1520Las an antioxidant, the monomer of chemical formula 5, and the monomer ofchemical formula 6. Thus, working samples 1 to 5 were obtained.

[0096] Furthermore, as comparative examples, two types of capacitors(comparative samples 1 and 2) were produced, using monomers representedby chemical formulae A and B.

[0097] Regarding the above-described 7 types of capacitors, (i) amoisture absorption capacitance change ratio and (ii) a high temperatureload capacitance change ratio were measured. For the capacitors producedwith the monomers of chemical formulae 9, A and B, the changes in thethickness when the capacitors were immersed in hot water were examined.The method for evaluation will be described later. Table 1 shows theevaluation results. TABLE 1 Moisture High absorption temperaturecapacitance load Thick- Anti- change ratio capacitance ness Monomeroxidant (%) change ratio change Working chemical Not +5.5 −1% to 0% Nosample 1 formula 9 added change Working chemical Not +7.0 −2% — sample 2formula 11 added Working chemical 3% by +7.0 −1% to 0% — sample 3formula 11 mass Working chemical Not +1.0 −1% to 0% — sample 4 formula 5added Working chemical Not +6.4 −1% to 0% — sample 5 formula 6 addedCom. chemical Not +18 −5% 200% to Sample 1 formula A added 300% Com.chemical Not +8.0 ≦−10% 200% to Sample 2 formula B added 300%

[0098] As seen from Table 1, the capacitors of working samples 1 to 5exhibited better characteristics than those of the capacitors ofcomparative samples 1 and 2 in the evaluation of both the moistureabsorption capacitance change ratio and the high temperature loadcapacitance change ratio. More specifically, capacitors having excellentcharacteristics even under high humidity and high temperature wereobtained by forming dielectric films of the capacitors with the monomersof the present invention having a molecular structure in which sulfurand an aromatic ring are covalently bonded or a molecular structure inwhich sulfur and an aromatic ring are bonded via an alkylene group.

[0099] Hereinafter, the method for evaluating the characteristics shownin Table 1 will be described in detail.

[0100] (i) The moisture absorption capacitance change ratio wasevaluated in the following manner. First, a capacitor was dried in a105° C. atmosphere for 10 hours, and the initial capacitance C₁₁ wasmeasured. The capacitance was measured while a sine wave with afrequency of 1 kHz and a voltage of 1 Vrms was applied to the capacitor.Thereafter, the capacitor was stored in an atmosphere at a temperatureof 60° C. and a relative humidity of 95% for 100 hours. Then, thecapacitance C₁₂ after the storage (the capacitance when the capacitorabsorbed moisture) was measured under the same conditions as the initialcapacitance was measured. The moisture absorption capacitance changeratio is a value represented by (C₁₂−C₁₁)/C₁₁×100 (%). The smaller themoisture absorption capacitance change ratio is, the higher thecapacitance stability in a humid atmosphere is, and such capacitorshaving a small change ratio are preferable as a product. Therefore, itis particularly important that the moisture absorption capacitancechange ratio is as small as possible.

[0101] (ii) The high temperature load capacitance change ratio wasevaluated in the following manner. First, a capacitor was dried in a105° C. atmosphere for 10 hours, and the initial capacitance C₂₁ wasmeasured. The capacitance was measured while a sine wave with afrequency of 1 kHz and a voltage of 1 Vrms was applied to the capacitor.Thereafter, the capacitor was stored for 50000 hours in an atmosphere ata temperature of 105° C. while a dc voltage of 16V was applied. Then,the capacitance C₂₂ after the storage was measured under the sameconditions as the initial capacitance was measured. The high temperatureload capacitance change ratio is a value represented by(C₂₂−C₂₁)/C₂₁×100 (%). A capacitor having a smaller absolute value ofthe high temperature load capacitance change ratio is less likely to beoxidized at high temperatures, and such a capacitor is preferable as aproduct. In particular, in recent years, the high temperature resistanceof electronic components has become important, as CPUs are operated at ahigh speed. Therefore, the smallness of the absolute value of the hightemperature load capacitance change ratio is an important indicationwhen evaluating capacitors.

[0102] (iii) The change in the thickness when capacitors were immersedin hot water was evaluated in the following manner. First, the thicknessof a capacitor was measured. Then, the capacitor was immersed in hotwater at 90° C. for 3.5 hours. Thereafter, the capacitor was taken outof the hot water and the thickness was measured again. Then, thethicknesses before and after immersion in hot water were compared. Thelarger the change in the thickness is, the more moisture the dielectricfilm absorbs, and the adhesion between the dielectric film and theelectrode film made of metal is degraded. Therefore, a capacitor havinga smaller change in the thickness has a higher adhesion between thedielectric film and the electrode film, so that such a capacitor ispreferable as a product.

[0103] Furthermore, the dielectric loss tangent (tanδ) was evaluatedwith respect to each sample, and the results were such that thecapacitors of working samples 1 to 5 exhibited characteristics equal tothose of comparative samples 1 and 2 or even better characteristics. Thedielectric loss tangent (tanδ) was measured while a sine wave with afrequency of 1 kHz and a voltage of 1 Vrms was applied to the capacitor.The smaller the dielectric loss tangent is, the smaller the powerconsumed by the capacitor itself is, so that such a capacitor having asmaller dielectric loss tangent is preferable as a product.

[0104] In the above-described embodiments and examples, the case wherethe electronic component of the present invention is a capacitor havebeen described. However, the electronic component of the presentinvention is not limited thereto, and any electronic components can beused, as long as the dielectric film described in the above embodimentsis provided. More specifically, for example, the present invention canbe used for coils, resistors, capacitive cells, support members of otherelectronic components or the like.

[0105] The embodiments of the present invention have been describedabove by way of examples. However, the present invention is not limitedto the above-described embodiments and can be applied to otherembodiments based on the technical idea of the present invention.

INDUSTRIAL APPLICABILITY

[0106] As described above, the present invention provides novelbis(4-mercaptophenyl) sulfide derivatives represented by generalformula 1. The bis(4-mercaptophenyl) sulfide derivatives represented bygeneral formula 1 of the present invention are useful for electroniccomponents, such as capacitors, coils, resistors, capacitive cells,support members of other electronic components or the like. When adielectric film is formed using the bis(4-mercaptophenyl) sulfidederivatives and is used in an electronic component, the electroniccomponent can have excellent characteristics even under high humidityand high temperature.

[0107] Moreover, the method of the present invention for producingbis(4-mercaptophenyl) sulfide derivatives makes it possible to producethe bis(4-mercaptophenyl) sulfide derivatives represented by generalformula 1 easily.

[0108] Moreover, according to the electronic component of the presentinvention, an electronic component having excellent characteristics evenunder high humidity and high temperature can be obtained. In particular,a high quality capacitor with reduced changes in the characteristics dueto the environment can be obtained by applying the present invention toa capacitor.

1. A bis(4-mercaptophenyl) sulfide derivative represented by generalformula 1

wherein R is hydrogen or a methyl group, and n is an integer of 1 to 4.2. The bis(4-mercaptophenyl) sulfide derivative according to claim 1,wherein R is hydrogen and n is
 2. 3. A method for producing abis(4-mercaptophenyl) sulfide derivative comprising: reactingbis(4-mercaptophenyl) sulfide represented by chemical formula 2 withω-haloalkyl alcohol having not more than 4 carbon atoms, therebyproducing an organic compound represented by general formula 3, andreacting alkyl ester acrylate or alkyl ester methacrylate with theorganic compound represented by general formula 3, thereby producing abis(4-mercaptophenyl) sulfide derivative of general formula 1

 wherein n is an integer of 1 to
 4.

 wherein R is hydrogen or a methyl group, and n is an integer of 1 to 4.4. (Cancelled)
 5. (Cancelled)
 6. (Cancelled)
 7. An electronic componentcomprising a dielectric film, wherein the dielectric film is formed byforming a thin film containing at least one type of monomer andpolymerizing the monomer in the thin film, and the monomer has amolecular structure in which sulfur and an aromatic ring are covalentlybonded or a molecular structure in which sulfur and an aromatic ring arebonded via an alkylene group.
 8. The electronic component according toclaim 7 further comprising a pair of electrodes opposed to each otherwith at least a part of the dielectric film interposed therebetween. 9.The electronic component according to claim 7, wherein the monomercomprises a monomer represented by general formula 1

 wherein R is hydrogen or a methyl group, and n is an integer of 1 to 4.10. The electronic component according to claim 7, wherein the monomercomprises a monomer represented by general formula 4

 wherein R is hydrogen or a methyl group.
 11. The electronic componentaccording to claim 7, wherein the monomer comprises a monomerrepresented by chemical formula 5


12. The electronic component according to claim 7, wherein the monomercomprises a monomer represented by chemical formula 6


13. The electronic component according to claim 7, wherein the thin filmfurther comprises an additive.
 14. The electronic component according toclaim 13, wherein the additive comprises an antioxidant.